Dormer Construction

Demolition Brochure

September, 2015

Dormer Demo BrochureDormer Construction’s Ltd (DCL) project experience spans some twenty years. Operating from offices in Rangiora we service demolition and civil works needs across the wider Canterbury region and South Island.

The company was founded by Peter E. Dormer sole owner and director of the company, in 1994 when he left school at the age of 17.

From a one man business the company has grown. We have a reputation for demonstrated commitment to quality and safety in delivering complex and highly demanding civil projects, large subdivision developments and demolition works. We have staff experienced and specialist in demolition works. Our skill base and portfolio of works has continued to grow in response to earthquake demolition works.in Christchurch demonstrating DCL capability as a multi-talented civil engineering company.

Download Demolition Brochure

Christchurch Girls High School Demolition

August, 2014

SCOPE

Dormer was awarded this contract from a RFT Following an application to Ministry of Education to be a panel (supplier) member for MOE’s demolition portfolio in Christchurch. The general scope of works involved the demolition of the school’s single-level auditorium, music rooms (100,000m2 adjoining an existing building) and associated site works and landscaping. Dormer were responsible for and managed; site set up, strip out, structural demolition and removal of material, removal of all in-ground foundations and services, redundant wastewater and storm water fixtures and fitting (co-ordinated with LOGIC’S separate subcontractors), site works including backfilling and grassing, and construction of weather-tight screen in the structural opening in the main entry lobby. A hidden layer of Asbestos was discovered in the roof-Dormer arranged for safe access to the area and managed the isolation, safe removal and disposal of asbestos using specialists contractors. Isolation of the whole site was paramount as deconstruction took place in a live school environment. Dormer co-operated and communicated readily with school staff regarding deconstruction impact. Where appropriate Dormer sequenced works to happen outside school hours.

PERFORMANCE

Environment

Nil incidents. Efficient separation of material to reduce waste to landfill.

Health and Safety

Nil incidents.  The discovery of asbestos was managed to ensure no harm or injury to Dormer staff, subcontractors, school pupils or staff.  Isolated site to restrict entry of hazardous zone.

Programme

Reflected submitted methodology and sequencing. While disrupted by discovery of asbestos, work was completed expediently.

Cost/Budget

Achieved. Approved Variations.

UoC Science Lecture Theatre Demolition

July, 2014

SCOPE

Controlled 17-staged deconstruction and removal of 1961 built 2-level campus lecture theatre building.
Dormer managed deconstruction activities and site access in the operating Ilam campus. The safety and protection of campus students and staff was paramount.  Dormer engaged high reach excavator (22m and 28m booms) and had all necessary demolition attachments to achieve staged “waterfall” demolition technique on a 42m2 footprint. Methodology for all 17stages principally followed deconstructing the building down to second floor and then ground floor level pulling debris towards the excavator. Structures included; shear walls, roofing trusses, inner double-shear wall stair and lift cases, concrete slab on grade, suspended concrete floor, plant room, glazed external perimeter wall, reinforced concrete, steel trusses, steel portal frames, structural steel stringers, joist purlins and steel roofing.  At all times the construction methodology was considered ‘live’ with Dormer being flexible to modify methods/approach once information on the building behaviour was confirmed.  Existing service tunnels were protected (bridged) during deconstruction.

PERFORMANCE

Environment

Work carried out on operating campus site (demolished building was connected to other existing buildings via link bridges). We provided due consideration of noise, dust and vibration and protection of campus assets. Dilapidation survey conducted.  All sewer and stormwater laterals were capped, surveyed and photographed. Water carts and water spray from high reach boom used to suppress dust. Disposed and recycled material where possible (steel, metals, clean crushed concrete and blocks).

Health and Safety

Floors were cleaned out thoroughly to ensure maximum debris loading and reduce collapse of the structure.  Soft fit out access provided and only approved access granted once high reach demolition began.  Nil incidents/accidents on operating university campus.

 

SCIENCE ALIVE BUILDING DEMOLITION

July, 2014

SCOPE

A complex and big building demolition. Being the former Christchurch Railway Station the building was designed and constructed in the late 1950s – one of the strongest government buildings built in its day. It had expansive basement ground floor, foundations including 870 reinforced concrete piles, each pile being 7.5 meters deep and filled with reinforced concrete,  and a further 3 floors, and a clock tower equivalent to seven stories high. The roof had reinforced concrete slabs supported by structural steel frames. The external walls were reinforced brickwork tied to the floors (reinforced concrete slabs encased in structural steel frames) at each levels. Complexities including the manual cutting of concrete encased steel beams, where the high-reach excavator or large shears on standard boom excavator where unable to reach and cut through. Every 10 minutes debris was removed from floors to ensure debris loading was not exceeded. The clearing of the floors was a set procedures to safeguard against any possible risk of collapse.

PERFORMANCE

Programme

Applied logical methodology and staged works over 6 month building deconstruction period.

Environment

DCL carried out dilapidation survey (supplied to CERA), asset protection, service disconnection and building monitoring. Specialist equipment was used to suit the nature of the site and surrounding environment. The basement was cleared of rubble, backfilled to ground level with engineered fill of aggregate, crushed concrete, crushed  bricks.

Health and Safety

Nil incidents. Safety was paramount at all times for public and staff due to the compromised building and the proximity to roads and the public. DCL carried out building stability monitoring using vertical surveys and crack monitoring during demolition and after significant earthquake after shocks.

HSBC BUILDING DEMOLITION

July, 2014

SCOPE

Complex demolition of ‘eccentric’ main structure requiring critical sequencing. The building comprised a perimeter moment-resisting seismic frame with gravity beams and columns internally. The perimeter seismic frames step in sequentially as the building rise and seismic demands reduce. As the rectangular seismic frame columns reduce they are replaced with purely gravity load resisting circular columns. The flooring comprised of a hi-bond steel tray reinforced concrete floor system spanning some 5.2 metres between the perimeter frames and internal gravity beams. The roof (26 metres above outside ground level) was lightweight steel cladding upon a structural steel frame. The south wall was constructed on the boundary and the majority of the frame in-filled with pre-cast concrete wall panels. The lift core structure was some 33 meters high.  DCL produced 3-D modelling to assist the client and staff in understanding the demolition sequence. This modelling provided a basis for analysing stability of the building at each stage and ensuring sight lines for the high excavator operator were maintained.

PERFORMANCE

Programme

Applied logical sequence to achieve completion of works in 3 months. Asbestos removal, retrieval of tenant items, soft strip out, protection to adjacent buildings, roof removal, pre-cast concrete removal, main building de-construction.

Environment

DCL carried out dilapidation survey (supplied to CERA), asset protection, service disconnection and building monitoring.

The project involved the protection of adjacent buildings including the Harley Chambers, a listed historic building, sited approximately 1 meter from HSBC work boundary.

Health and Safety

Nil incidents. DCL carried out building stability monitoring using vertical surveys and crack monitoring during demolition and after significant earthquake after shocks.

 

ACC BUILDING DEMOLITION

July, 2014

SCOPE

Controlled deconstruction and removal of all structures, slabs, and foundations and the decommissioning of an Orion Substation within the building. The 5-storey office building was stripped out, office fittings and furniture salvaged for the client. Prior to strip out and salvage a full verticality, crack, and damage survey was carried out on the building and monitoring was carried out throughout to ensure the stability of the structure and the safety of the workers inside the building. DCL produced 3-D modelling to assist the client and staff in understanding the demolition sequence. This modelling provided a basis for analysing stability of the building at each stage. DCL chose a “waterfall” type deconstruction using a ZX470 super high reach demolition excavator.  The concrete “moment frame” structure of this building, lent itself perfectly to this type of demolition.

PERFORMANCE

Programme

The demolition was carried out on time to meet strict deadline for the settlement of the purchase of the land by the CCDU as part of the “Eastern Frame”.

Environment

DCL carried out dilapidation survey, asset protection, service disconnection and building monitoring. Specialist equipment was used to suit the nature of the site and surrounding environment. Traffic Management Plans implemented for work adjacent main arterial routes.

Health and Safety

Nil incidents. Safety was paramount at all times for public and staff due to the compromised building and the proximity to roads and the public. DCL carried out building stability monitoring using vertical surveys and crack monitoring during demolition.